1. Technical Field
This invention relates generally to electronic imaging devices, and more particularly, to a system that reduces the effects of cross-talk in electronic imaging devices.
2. Related Art
Electronic imaging devices, or imagers, have broad applications in many areas such as in the commercial, consumer, industrial, medical, defense and scientific fields. The electronic imaging devices convert a received optical image, such as an image of an object, into a signal corresponding to the received image. A typical electronic imaging device includes a photosensor to sense the received optical image.
Photosensors in electronic imaging devices are typically formed of an array structure, with rows and columns, of photodetectors (such as photodiodes, photoconductors, photocapacitors and photogates) that generate photo-charges corresponding to the light radiation received by each respective photodetector. The photo-charges are created by photons striking the surface of the photodetectors, which are typically constructed of an appropriate semiconductor material. As photons strike the surface of a photodetector, free charge carriers (i.e. electron-hole pairs) are generated in an amount proportional to the incident photon radiation upon the photodetector. A signal is then generated corresponding to the amount of that incident photon radiation. The collective signals from each respective photodetector may then be utilized as desired, such as for displaying or electronically storing a corresponding image or for providing particular relevant information regarding the image.
During operation, an undesirable phenomenon generally termed as ‘cross-talk’ occurs among adjoining or adjoining photodetectors in a photosensor. Because of this phenomenon, some photo-charges leak from a photodetector to adjoining photodetectors, and influence (i.e. corrupt) the signals generated by the adjoining photodetectors. Similarly, the photodetector also receives some cross-talk photo-charges from its adjoining photodetectors. Such cross-talk, therefore, undesirably corrupts the signals generated by a photodetector during operation of the corresponding electronic imaging device. Depending on the particular environment in which the electronic imaging device is being used, such inaccuracies can be significant, and sometimes even dangerous. For example, in an electronic imaging device used in a medical environment, such as when a surgeon performs micro-surgery on a patient with the assistance of an electronic imaging device, corrupted signals from the electronic imaging device may blur the image presented to the surgeon. The blurred image can impact the surgeon's performance during the surgical procedure, which can result in dangerous errors during the surgery.
To further complicate matters, cross-talk is unpredictable because the amount of cross-talk typically varies continuously depending upon the amount of incident photon radiation upon the surface of the particular photodetector, the wavelength of the light comprising that incident photon radiation, and the like. Therefore, the amount of cross-talk typically lacks a precise predictable order. Furthermore, the spatial location of the photodetectors with respect to each other also contributes to the amount of cross-talk in a particular photosensor. Typically, the amount of cross-talk decreases with an increase in the distance between adjacent photodetectors. All these variables add to the indefiniteness and unpredictability of cross-talk among adjoining photodetectors during the operation of an electronic imaging device.
Efforts to adjust cross-talk in electronic imaging devices have not been entirely successful. Systems designed for adjusting cross-talk are only somewhat effective because they tend to utilize a predetermined formula for cross-talk adjusting the value of the signals from the photodetectors. Many significant variables, such as the amount of light incident upon the photodetector, its wavelength, the amount of light incident upon adjoining photodetectors, its wavelength, the distance of the photodetector from the adjoining photodetectors, and the like, tend to be overlooked. Such systems, therefore, are not fully effective in adjusting cross-talk in signals from photodetectors in electronic imaging devices.
It is, therefore, desirable to provide an improved system for reducing the effects of cross-talk in signals from photodetectors in an electronic imaging device. More particularly, there is a need for an improved system that more accurately adjusts the effects of cross-talk in photodetector signals, which includes taking into consideration the amount of incident photon radiation upon a particular photodetector, the wavelength of the incident photon radiation upon that photodetector, the amount of incident photon radiation upon adjoining photodetectors, the wavelength of the incident photon radiation upon those adjoining photodetectors, and the like. Accordingly, this invention is directed to overcoming one or more of the problems set forth above.